FSO中继系统及其关键技术研究

The main research contents in this project can be summarized as follows: 1) Consider a mixed RF/FSO system with multiuser diversity at the RF end, where both RF and FSO links are assumed to be generalized fading. Based on this system model, analytical results for the outage probability and error rate are derived. To investigate the system diversity order, we also present the high-SNR asymptotic analysis. 2)Consider a FSO satellite communication system where a satellite intends to communicate with the terrestrial user with the help of a relay. Based on the different location of the relay, we propose three different transmission schemes and analyze their system performance. 3) Consider a MIMO FSO system in the presence of spatial correlation. We propose a simple statistical math model. To improve the system performance, an aperture selection scheme is proposed and the system performance is analyzed. 4) Consider a FSO two-way relaying with variable relaying gain. By using AF protocol, outage probability expression is derived and the effects of different system parameters on the system performance are investigated. 5) Consider a two-way relaying network over composite channels. In a conclusion, these research results will provide some theoretical bases for the application of the FSO technique.

本项目将围绕自由空间光通信及协作分集网络，开展以下工作：1）首先考虑一个RF端具有多用户分集的混合RF/FSO系统，其中RF和FSO链路均为通用分布，基于此模型，分别导出系统中断概率及误码率表达式，另外还给出高信噪比下的渐近分析来观察系统分集度。2）考虑一个基于FSO的卫星中继系统，基于不同的中继地理位置，我们将给出3种不同的传输方案，分析各自的系统性能并加以比较。3）考虑一个存在空间相关的空间分集FSO系统，提出简化实用的数学统计模型，以改善系统性能为目的，提出接收端的孔径选择方案并给出系统性能分析。4）考虑一个变增益的FSO双向中继网络，采用AF协议，导出系统中断概率表达式并观察各系统参数之间的相互影响关系。5）考虑一个复杂信道下的RF双向中继网络，其中信道衰落为通用分布。总体而言，这些研究结果将为FSO技术的实际应用提供理论支撑作用。

自由空间光通信可以提供高速率的传输而不需要额外的频谱资源已成为学术界的研究热点，另外可重构智能表面技术可以提供智能的无线电环境在近2年引起广泛关注，本项目主要围绕自由空间光通信、可重构智能表面技术及其相关技术，开展了一系列的前沿性研究，涉及到多天线技术、NOMA技术及物理层安全等。在该项目执行期间，发表署名该基金资助的论文32篇，其中IEEE期刊论文27篇（含12篇IEEE Transactions论文），ESI高被引论文3篇，IEEE ComSoc Besting Readings论文2篇。该项目的研究成果为自由空间光通信及可重构智能表面技术的应用提供一些理论指导意义。